glenn



L. W. GLENN METHOD OF DISPERSING FLUID BENEATH SLAB FLOORS Filed March1, 1961 March 17, 1964 2 Sheets-Sheet 1 INVENTOR. LESTER W. GLENN BY NM?(5. W

l I m IOA ATTORNEY March 17, 1964 w. GLENN 3,124,893

METHOD OF DISPERSING FLUID BENEATH SLAB FLOORS Filed March 1, 1961 2Sheets-Sheet 2 FIG. 5

Mr. V

v Fill/I n I IOE INVEN TOR. LESTER W. GLENN ATTORNEY United StatesPatent 3,124,893 METHOD OF DISPERSING FLUID BENEATH SLAB FLGORS LesterW. Glenn, 1825 14th St. NW., Bradenton, Fla. Filed Mar. 1, 1961, Ser.No. 92,638 14 Claims. (Cl. 43-124) The present invention relates to amethod of dispersing fumigant or other fluid into the earth supporting aslab floor, and the primary object of the invention is to provide aprocedure whereby a fluid may be caused to permeate the ground beneathsuch a slab, with minimum hazard to conduit means embedded in the slabor located beneath the slab, and in such a fashion as to facilitatesubstantially complete obscuration of the scars resulting from theoperation.

In recent years, the practice of erecting homes and other buildings uponslabs, usually of concrete, directly supported upon the earth has becomevery popular primarily, but not entirely, in the warmer regions of thecountry. Such construction, of course, renders the permeation of theground beneath the slab with a fumigant or other fluid, for destroyingand/ or inhibiting the ingress of termites and other pests, or for anyother purpose, quite diflicult. It is not feasible effectively topermeate the ground beneath such a slab of substantial dimensions byrodding or even drilling from points outside the perimetral boundariesof the slab, and even with relatively small slabs, such rodding and/ordrilling involves a substantial hazard of damage to pipes, cables,electrical conduits and the like which may have been laid beneath theslab.

Where the slab itself constitutes the building floor, with its uppermostsurface exposed, attempts have heretofore been made to disperse afumigant into the ground by drilling vertically through the slab andforcing the fumigant through the passages so formed. So far as I amadvised, however, it has always heretofore been necessary, in such aprocedure, to drill passages having diameters of at least /2 in order toaccommodate nozzles which must necessarily include sealing meansexpansible into contact with the passage walls. Where the floor includesany kind of attached covering for the slab however, such as asphalt,rubber or vinyl tile, linoleum or carpet cemented to the slab, aterrazzo finish, or ceramic tile, slate, fiagstones or other brittle,separate elements set in a mortar bed, such drilling has been impossiblewithout leaving scars incapable of substantial obliteration orobscuration. Prior to my invention, it has been necessary, in the caseof tile or similar coverings, to remove spaced tiles from the floorcovering before drilling through the slab; and, since it is impossiblethus to remove such tiles consistently without damage thereto and it isequally impossible to match tiles which have been in use, it has alwaysheretofore been necessary to replace such removed elements withcontrasting elements, resulting in a substantial modification in theappearance of the repaired floor. In the case of terrazzo finishes, anyavailable filling for a relatively large hole drilled through the finishwill inevitably be flagrantly prominent; and where such a slab iscovered with cemented carpeting, it has been impossible to makeunobvious repairs Through the use of the procedures and the apparatushereinafter to be disclosed, however, I have found it possibleeffectively to permeate the ground beneath such a slab, no matter whichof the above listed coverings may constitute a part of the floor, andyet to obliterate substantially completely all traces of scars after thechemical has been dispersed.

To the accomplishment of the above and related objects, my invention maybe embodied in the steps described in the following specification and inthe forms of apparatus illustrated in the accompanying drawings,attention being called to the fact, however, that the drawings areillustrative only and that the specific procedures described are by wayof illustration only and that change may be made in the specificconstructions illustrated and described or in the specific steps stated,so long as the scope of the appended claims is not violated.

FIG. 1 is a more or less diagrammatic illustration of the apparatus andthe operational steps embodying my invention as applied to a slab fioorincluding a covering of composition tile;

FIG. 2 is a similar illustration in connection with a floor having aterrazzo finish;

FIG. 3 similarly illustrates four steps in the procedure when the floorcovering is made of hardwood;

FIG. 4 illustrates two of the steps involved in the application of myprocedure to a floor having a cemented, long-nap carpet cover;

FIG. 5 illustrates two of the steps involved where the floor covering isshort-nap carpeting; and

FIG. 6 illustrates portions of the procedure which is used where thefloor covering comprises separate, brittle elements set in a mortar bed.

Referring more particularly to the drawings, it will be seen that I haveillustrated in FIG. 1 a concrete slab 10 supported upon the earth l1 andhaving a covering 12 of asphalt, rubber, vinyl or similar tile.Accordingly to the present invention, passages are substantiallyvertically drilled, at suitably spaced intervals over the floor, throughthe covering and through the slab, a plurality of such passages, insuccessive stages of the process, being illustrated at 13A, 13B, 13C,13D and 13B. Each such passage has a diameter not substantiallyexceeding one-fourth inch, and care should be taken to exert a lightpressure against the drill as it progresses through the tile, in ordernot to crack or shatter the tile, and to prevent bowing or canting ofthe drill as it progresses through the slab 10. If the drilling is doneskillfully, the entire passage through the slab and floor covering willbe uniform in diameter, the regions of the tile surrounding each passagemouth will not be damaged and only a very small annular bulge or collar30 will be raised in the material of the tile immediately adjacent theportion 14 of each passage.

Preferably, the next step in the process will be to insert a rod 15through each passage, and to push the rod into the earth to a depth ofapproximately 18" beneath the bottom surface of the slab, therebyforming, in the earth, an extension 16 of each passage 13. While thisrodding step is desirable, in order to accelerate the rate at whichfluid can be caused to permeate the earth adjacent each passage, it isnot essential to the accomplishment of the primary objects of theinvention.

Now, a plug 17 is pushed into each passage, in the manner illustrated inconnection with the passage 13C of FIG. 1, preferably to a depth belowthe level of the tile covering 12. The insertion of the plug 17 may, ifdesired, be facilitated by applying to its peripheral surfaces a lightcoating of cylinder oil or cup grease. The plug should have asubstantially fluid tight engagement with the walls of the passage, andI presently prefer to use a rubber or other transaxially-compressible,elastic grommet having an axial bore 18 therethrough. Preferably, theequilibrium diameter of the plug 17 will slightly exceed the internaldiameter of the passage in which it is to be seated so that, as the plugis pushed home, it will be transaxially compressed, thereby attaining apressurized engagement with the peripheral surface of the bore andslightly constricting the bore 18.

A reservoir 19 may preferably be mounted upon a plurality of legs 20'and is provided with a removable closure cap 21. Said reservoir isprovided with an inlet 22 adjacent its upper end, to which is connectedconduit means 23 such as a hose leading from a suitable source (notshown) of compressed air. Near its bottom, the reservoir is providedwith an outlet 24 to which is connected conduit means '25, which ispreferably a flexible hose; and a suitable nozzle 26, preferablyincluding a strainer (not shown), is carried at the free end of the hose25 and in turn carries a hypodermic needle 27. I have found that aconventional l6-gauge stainless steel hypodermic needle, which may besilver-soldered to the tip of the nozzle 26, serves admirably for thepurposes of my invention.

The needle 27 is forced axially through the plug 17 to position itsdistal end within the passage 13 at a point beneath the plug 17. Wherethe plug is a grommet, as illustrated, the needle will, of course, bepushed through the bore 18 thereof; but it will be obvious that a solidplug could be used and that the hypodermic needle could force its ownway through such a plug. In any event, the parts should be soproportioned and designed that, when the needle is positioned in themanner illustrated in the passage 13D of FIG. 1, the material of theplug will elastically grip the needle to define a substantially fluidtight seal thereabout.

A measured quantity of fluid to be injected into the earth is filledinto the reservoir 19 and the cover 21 is tightly seated on thereservoir. Now, compressed air is fed to the reservoir 19 through theinlet 22. to force the fumigant through the hose 25 and needle 27 intothe passage 13D. The fumigant will fill the passage 13D and theassociated extension 16 and will be dispersed into the ground in thevicinity of said passage and its extension. The rate of flow, of course,will depend upon the characteristics of the soil and upon the pressurevalue of the air supplied to the reservoir. Eventually, and usuallywithin one to two minutes, the measured quantity of fumigant, which isusually one to two pints, will have been discharged from the reservoirand through the needle 27 into the passage 13 and the surrounding regionof the earth. Quivering of the hose 25 will usually signal the fact thatall of the liquid has been discharged and that air is passing throughthe hose. Now, the supply of air to the reservoir is cut off and theapparatus is allowed to stand for a brief period during which most ofthe pressure within the reservoir will bleed off into the passage 13.Either by removing the cap 21 or by disconnecting the hose 23, theinterior of the reservoir, the hose 25 and the needle 27 will now bereturned to atmospheric pressure, whereafter the needle will bewithdrawn from the plug. The waiting period is for the purpose ofensuring against the possibility of drip from the needle, after it iswithdrawn, since the fumigant (which is preferably ethylene dibromide)may damage floor coverings.

Sometimes it may be desirable to inject a fluid which is gaseous atatmospheric temperatures and pressures and which is available in theliquid phase in pressure cylinders. In such case, such a cylinder may bedirectly connected to the reservoir 19 through a suitable fitting at 21,and the whole assembly may be mounted on a weighing scale. The reservoir19 will thus act as a receiver, the evaporation pressure of the fluidwill enforce flow into the soil and the amount of fluid injected can bedetermined by the weight reduction of the assembly.

Now, a preferably wooden dowel having a diameter substantially equal tothe diameter of the passage 13 and a length four to five times itsdiameter, is driven into the passage 13, thereby forcing the plug 17more deeply into the passage and, at the same time, establishing asubstantially fluid tight engagement between the lower end of the doweland the upper end of the plug, thus sealing the plug bore 18.Preferably, the dowel is water-soaked before insertion. As isillustrated in connection with the passage 13E in FIG. '1, the dowelwill preferably be driven to a depth such that its upper end is flushwith the juncture between the slab 1d and the floor covering 12.

From a new piece of material corresponding to the material of the floorcovering 12 and closely approximately the color of such floor covering,there is punched a plug 29. Such a plug may readily be produced with aconventional metal punch, bringing the die thereof against the top sideof the tile and the punch against the bottom side. If pressure isapplied to the punch slowly and carefully, cracking or shattering of thetile or of the plug may be avoided. The slug 29 so punched out of a newtile will be a truncated cone 4 in diameter at its bottom and 7 at itstop. This tapered shape, and the slight raised collar 30 above-mentionedaround the hole 14 in the floor covering, will facilitate insertion ofthe plug and will contribute to sealing the hole perfectly so that it isdiflicult to detect the patch even when its location is known. The plug29 is inserted in the hole 14B and is tapped home with a smooth facedhammer until the plug is perfectly flush and the collar 30 has beensubstantially eliminated. Preferably, but not necessarily, a drop ofcement will be applied to the bottom surface of the plug before it isinserted in the hole 14E, so that the plug will be adhesively secured tothe upper end of the dowel 28.

The above procedure may be followed exactly in the case of a floor inwhich the covering is linoleum or its equivalent.

Where the floor consists solely of the concrete slab 10, without anycovering thereon, the above procedure is followed precisely, except ofcourse for the provision and insertion of the plug 29 and except thatthe dowel 28 will be driven to a level significantly below the exposedsurface of the slab and the portion of the passage above the upper endof the dowel will be filled with concrete conforming to thecharacteristics of the concrete from which the slab is formed.

In FIG. 2, I have illustrated the procedure where the floor consists ofa slab 10A and a terrazzo covering 31. Such a covering, of course,consists of a mass of aggregate largely comprising relatively largeparticles 32, embedded in a mass of non-shrinking cement 33, the exposedsurface of the covering having been ground or polished after setting toproduce a variegated appearance. In the exposed surface of such acovering, it is always possible to find many areas more than A" indiameter, scattered over the surface, at which only the cement isexposed. Selecting such an area for each passage, a suitable number ofsuitably spaced passages 34 will be drilled through the slab NA and itscovering 31. Now, an extension 35 is rodded beneath each such passageand thereafter a plug 17 is seated in each passage 34. In this case, itis not necessary, though it may be advisable, to insert the plug to adepth below the bottom of the floor covering 31. As before, the needle27 is inserted through the plug 17 and the fumigant is similarly forcedinto the space below the plug. After the needle is withdrawn, a dowel 28is driven into the passage to force the plug 17 more deeply thereintoand to seal the outer end of the plug; and thereafter the portion of thepassage above the upper end of the dowel is filled with a suitable,nonshrinking cement corresponding in character and color to the cementcomponent of the original terrazzo cover.

In FIG. 3, I have illustrated a concrete slab 103 having a covering 41which may be parquet or any other suitable hardwood arrangement. In thiscase, the passages i2 are carefully drilled through the covering and theslab, and the rodding step above described is performed to produceextensions 43. A plug .17 is now seated in each passage, and is pressedto a level significantly below the bottom surface of the floor covering.The needle 27 is inserted and the fumigant is forced into each passageto permeate the soil beneath the slab. After withdrawal of the needle, adowel 28 is driven into each passage to force the plug 17 more deeplythereinto and to seal the outer end of the plug.

Here, the problem of obscuring the repair is somewhat complicated by thefact that the grain of the flooring runs horizontally while the grain ofordinary wood dowels runs axially thereof. Now available on the market,however, is a product known as a furniture dowel which is a wood plugwith the grain running perpendicular to the axis of the piece. Selectingsuch a furniture dowel which closely matches the grain of the drilledpiece of the flooring 41, and which has a diameter conforming to thediameter of the bore through the flooring, the dowel 28 is driven to adepth such that its upper end is positioned below the exposed surface ofthe floor covering 41 to a degree precisely equal to the axial dimensionof the selected furniture dowel. With a drop of glue on the bottom endthereof, the furniture dowel is now inserted in the upper end of thepassage 42 and is tapped home until its upper surface is precisely flushwith the exposed surface of the flooring.

In FIG. 4, I have illustrated the first and last steps of the procedureto be followed Where the floor comprises a slab WC and a covering 51 oflong-nap carpeting. In such a situation, the woven or otherwise-formedbacking 52 of the carpeting is conventionally cemented to the uppersurface of the slab 10C.

In such a situation, the long nap 53 of the carpet is carefullyseparated at suitably spaced points and the passages 54 are drilledstraight through the carpet backing 52 and the slab 10C, substantiallywithout affecting the nap 53. After the fumigant has been dispersed intothe soil in the manner above-described, a dowel 23 is driven into eachpassage to force the plug 1'7 more deeply into the passage and to sealthe upper end of said plug. The dowel will be driven to a depth suchthat its upper end is below the upper surface of the carpet backing 52;and now the long nap 53 of the carpet is brushed back into place toobscure completely the tiny perforations 55 which have been driventhrough the backing 52.

In FIG. I have illustrated the first and last steps which are used whenthe covering 61 for the slab MD is short-nap carpeting cemented to theslab. In this case, the carpet backing 62. may be similar to the backing52, but the nap 63 of the carpet is too short effectively to cover evena quarter inch hole through the backing 62.

A A" or slightly larger slug 65 of carpeting is released from the mainbody of the carpeting by a circumscribing cut which may be made by meansof a thin tube 64 ground sharp at one end. When the sharpened end of thetube is held against the carpeting and carefully tapped with a hammer,its sharpened edge will be driven through the carpet backing and intoengagement with the upper surface of the slab D. Now, if a drop ofsolvent for the cement which secures the carpeting to the slab isapplied to the slug 65, it can be carefully loosened and removed. Aftersuch removal, the passage 66 may be drilled through the slab 10D withoutdamaging the carpet; and the fumigant may be dispersed into the earthbeneath the slab in the manner above-described. After removal of theneedle, a dowel 28 will be driven into the passage 66 to drive the plug17 more deeply into said passage and to seal the upper end of thepassage. In this case, the dowel is driven to such a depth that itsupper end is flush with the upper surface of the slab ltlD. Now, a dropof suitable cement is applied to the bottom surface of the (carefullydried) slug 65 and the slug is reinserted into the carpet body andpressed into engagement with the upper end of the dowel 28 where it willbe adhesively secured to obscure any indication of damage to the carpet.

FIG. 6 illustrates the first and last steps to be followed in workingwith a floor consisting of a slab 10B and a covering 71 comprisingseparate brittle elements 72 such as ceramicrtile, fiagstones or thelike set in a bed 73 of mortar and separated by tongues 74 constitutingportions of the mortar bed.

Customarily, such tile or similar elements 72 are separated by distancesexceeding one-fourth inch so that the transverse dimension of eachtongue 74 is more than one-fourth inch. Passages 75 according to thepresent invention may, therefore, be drilled through the mortar bed andthe slab at suitably spaced points, each of which is located in one ofthe tongues 74. After completion of the fumigant-dispersing step andwithdrawal of the needle, a dowel 28 may be driven into each passage 75to force the plug 17 more deeply into such passage and to seal the upperend of such plug. In this case, the dowel will be driven to a depth suchthat its upper end is significantly below the exposed surface of thecorrespending tongue 74, and the portion of the passage above the dowelmay be filled with mortar as at 76 corresponding in character to themortar which constitutes the appropriate tongue.

As is clearly illustrated in the drawings, the axial dimension of theplug 17 Will preferably be at least equal to its transaxial dimension,in order that the plug may constitute an effective and substantiallyfluid tight seal against escape of fumigant, during the dispersingoperation, toward the upper end of the passage.

Of course, the process as above described is only one part of a completeextermination job, and perimeter trenching and ground-treating should bedone, in addition to the above operations, as in any other type oftreatment. Yearly perimeter ground treatment with dieldrin or chlordaneto establish a chemical barrier from the surface to the ground waterlevel is also desirable.

Experience has indicated that ethylene dibromide does not seep upwardlyfrom beneath such a slab after dispersion according to the proceduresabove described. There is a possibility that plantings closely adjacenta foundation may be injured by the treatment if the footings areshallow. Care must be taken to avoid spilling ethylene dibromide insidethe building, as it is a very powerful solvent and will ruin asphalttile, for instance, before it can be wiped up. For this reason, extremecare must be taken against drippage from the needle and the reservoir 19should be refilled only outside the building. Additionally, standardprecautions against breathing the vapors in confined areas and againstcontact of the liquid with skin or clothing should be observed.

.1 have found that normally acceptable plugs 17 may be produced bycutting quarter inch diameter automotive ignition cable at approximatelyone inch intervals, slipping the insulation off the wire strands andcutting one inch pieces into quarter inch lengths. Care must beexercised to extract all strands of wire from the rubberoid pieces inorder to ensure a substantially fluid tight seal between the grommet andthe needle.

I claim as my invention:

1. The method of dispersing a fluid into the earth sup porting a slabfloor, which compirses the steps of forming through such a slab and anycovering thereon a passage having a major transverse dimension notsubstantially exceeding one-fourth inch, seating within said passage atransversely-elastic plug conformable to said passage in cross section,having equilibrium transverse dimensions at least equal to thetransverse dimensions of said passage and having an axial length atleast equal to its transverse dimensions, forcing a tubular elementaxially through said plug and into the portion of said passage belowsaid plug with the elastic material of said plug gripping the walls ofsaid tubular element in substantially fluid-tight relation, forcing afumigant through said tubular element to permeate the earth beneath saidslab, with drawing said tubular element from said plug while leavingsaid plug in place in said passage, and promptly thereafter driving asnugly-fitting dowel into the upper end of said passage and intointimate, sealing engagement with the upper end of said plug.

2. The method of dispersing a volatile fluid into the earth supporting aslab floor, which comprises the steps of forming through such a slab andany covering thereon a passage having a major transverse dimension notsubstantially exceeding one-fourth inch, seating within said passage atransversely-elastic plug conformable to said passage in cross section,having equilibrium transverse dimensions at least equal to thetransverse dimensions of said passage and having an axial length atleast equal to its transverse dimensions, forcing a tubular elementaxially through said plug and into the portion of said passage belowsaid plug with the elastic material of said plug gripping the walls ofsaid tubular element in substantially fluid-tight relation, forcing avolatile fluid through said tubular element to permeate the earthbeneath said slab, withdrawing said tubular element from said plug whileleaving said plug seated in said passage, and promptly thereafterdriving a snugly-fitting dowel into the upper end of said passage todrive said plug more deeply into said passage.

3. The method of dispersing a fluid into the earth supporting a slabfloor, which comprises the steps of forming through such a slab and anycovering thereon a passage having a major transverse dimension notsubstantially exceeding one-fourth inch, seating within said passage atransversely-elastic plug conformable to said passage in cross section,having equilibrium transverse dimensions at least equal to thetransverse dimensions of said passage and having an axial length atleast equal to its transverse dimensions, forcing a tubular elementaxially through said plug and into the portion of said passage belowsaid plug with the elastic material of said plug gripping the walls ofsaid tubular element in substantially fluid-tight relation, forcing avolatile fluid through said tubular element to permeate the earthbeneath said slab, withdrawing said tubular element from said plug whileleaving said plug seated in said passage, promptly thereafter driving asnugly-fitting dowel into said passage to a depth such that the lowerend of said dowel intimately and sealingly engages the upper end of saidplug and the upper end of said dowel is sunk below the exposed surfaceof said floor including any covering thereon, and filling the portion ofsaid passage above said dowel with a plug of material conforming incharacter to the exposed surface of said floor.

4. The method of claim 1 in which said plug is a rubberoid grommet.

5. The method of claim 1 in which said tubular element is a hypodermicneedle.

6. The method of claim 5 in which said plug is a rubberoid grommet.

7. The method of claim 1 which includes the step of rodding the earthbeneath the lower end of said passage to a depth of at least twelveinches before seating said plug.

8. The method of dispersing a fluid into the earth supporting a floorcomprising a continuous slap with a covering of cemented, shearablecomposition material, which comprises the steps of drilling a passagethrough said covering and said slab, said passage having a diameter notsubstantially exceeding one-fourth inch, seating within said passage,below the level of said covering, a cylindrical plug of elastic materialhaving an equilibrium diameter at least equal to the diameter of saidpassage and having an axial length at least equal to its equilibriumdiameter, forcing a tubular element axially through said plug and intothe portion of said passage below said plug with the elastic material ofsaid plug gripping the walls of said tubular element in substantiallyfluid-tight relation, forcing a volatile fluid through said tubularelement to permeate the earth beneath said slab, withdrawing saidtubular element from said plug while leaving said plug seated in saidpassage, promptly thereafter driving a snugly-fitting dowel into saidpassage to a depth such that the lower end of said dowel intimately andsealingly engages the upper end of said plug and the upper end of saiddowel is sunk below the level of said covering, cutting from a piece ofmaterial conforming to said covering a plug dimensioned sungly to fitWithin that por- '8 tion of said passage which penetrates said covering,and inserting said plug in place to fill said last-named passageportion. 7

9. The method of dispersing a fluid into the earth supporting a floorcomprising a continuous slab with a terrazzo covering, which comprisesthe steps of selecting a spot in the exposed surface of the terrazzowhere no aggregate particle is exposed, drilling, at that spot, apassage through said covering and said slab, said passage having adiameter not substantially exceeding one-fourth inch, seating withinsaid passage a cylindrical plug of elastic material having anequilibrium diameter at least equal to the diameter of said passage andhaving an axial length at least equal to its equilibrium diameter,forcing a tubular element axially through said plug and into the portionof said passage below said plug with the elastic material of said pluggripping the walls of said tubular element in substantially fluid-tightrelation, forcing a volatile fluid through said tubular element topermeate the earth beneath said slab, withdrawing said tubular elementfrom said plug while leaving said plug seated in said passage, promptlythereafter driving a snugly-fitting dowel into said passage to a depthsuch that the lower end of said dowel intimately and sealingly engagesthe upper end of said plug and the upper end of said dowel is sunk belowthe exposed surface of the terrazzo, and filling the portion of saidpassage above said dowel with non-shrinking cement conforming in colorto the immedi ately contiguous area of the original terrazzo.

10. The method of dispersing a fluid into the earth supporting a floorcomprising a continuous slab with a hardwood covering, which comprisesthe steps of drilling a passage through said covering and said slab,said passage having a diameter not substantially exceeding onefourthinch, seating Within said passage a cylindrical plug of elastic materialhaving an equilibrium diameter at least equal to the diameter of saidpassage and having an axial length at least equal to its equilibriumdiameter, forcing a tubular element axially through said plug and intothe portion of said passage below said plug with the elastic material ofsaid plug gripping the walls of said tubular element in substantiallyfluid-tight relation, forcing a volatile fluid through said tubularelement to permeate the earth beneath said slab, withdrawing saidtubular element from said plug while leaving said plug seated in saidpassage, promptly thereafter driving a snugly-fitting dowel into saidpassage to a depth such that the lower end of said dowel intimately andsealingly engages the upper end of said plug and the upper end of saiddowel is sunk below the exposed surface of said covering, and insertingin place a furniture dowel to close the opening through said coveringflush with the exposed surface of said covering.

11. The method of dispersing a fluid into the earth supporting a floorcomprising a continuous slab with a cemented, long-nap carpet covering,which comprises the steps of separating the nap of said covering at aselected spot to expose a minute area of the carpet body, drilling, atthat spot, a passage through the carpet body and said slab, said passagehaving a diameter not substantially exceeding one-fourth inch, seatingwithin said passage, below the level of said covering, a cylindricalplug of elastic material having an equilibrium diameter at least equalto the diameter of said passage and having an axial length at leastequal to its equilibrium diameter, forcing a tubular element axiallythrough said plug and into the portion of said passage below said plugwith the elastic material of said plug gripping the walls of saidtubular element in substantially fluid-tight relation, forcing avolatile fluid through said tubular element to permeate the earthbeneath said slab, withdrawing said tubular element from said plug whileleaving said plug seated in said passage, promptly thereafter driving asnugly-fitting dowel into said passage to a depth such that the lowerend of said dowel intimately and sealingly engages the upper end of saidplug and the upper end of said dowel is sunk below the level of saidcarpet body, and thereafter brushing the nap of the carpet back toconceal the hole through the carpet body.

12. The method of dispersing a fluid into the earth supporting a floorcomprising a continuous slab with a cemented, short-nap carpet covering,which comprises the steps of isolating a slug of carpet With acircumscribing cut, applying a cement-solvent to said slug to loosen thesame from said slab and removing said slug intact, then drilling, at thepoint of said slab exposed by removal of said slug, a passage throughsaid slab, said passage having a diameter not substantially exceedingone-fourth inch, seating within said passage, below the level of saidcovering, a cylindrical plug of elastic material having an equilibriumdiameter at least equal to the diameter of said passage and having anaxial length at least equal to its equilibrium diameter, forcing atubular element axially through said plug and into the portion of saidpassage below said plug with the elastic material of said plug grippingthe walls of said tubular element in substantially fluid-tight relation,forcing a volatile fluid through said tubular element to permeate theearth beneath said slab, withdrawing said tubular element from said plugwhile leaving said plug seated in said passage, promptly thereafterdriving a snugly-fitting dowel into said passage to a depth such thatthe lower end of said dowel intimately and sealingly engages the upperend of said plug and the upper end of said dowel is flush with theexposed surface of said slab, and thereafter cementing said slug to theupper end of said dowel to fill the hole in said carpet.

13. The method of dispersing a fluid into the earth supporting a floorcomprising a continuous slab having a covering of brittle, separateelements set in, and separated by, a bed of mortar, which comprises thesteps of drilling, through the mortar joint between two of such elementsand through said slab, a passage having a diameter not substantiallyexceeding one-fourth inch, seating within said passage, at a level belowthe upper surface of said slab, a cylindrical plug of elastic materialhaving an equilibrium diameter at least equal to the diameter of saidpassage and having an axial length at least equal to its equilibriumdiameter, forcing a tubular element axially through said plug and intothe portion of said passage below said plug with the elastic material ofsaid plug gripping the walls of said tubular element in substantiallyfluid-tight relation, forcing a volatile fluid through said tubularelement to permeate the earth beneath said slab, withdrawing saidtubular element from said plug while leaving said plug seated in saidpassage, promptly thereafter driving a snugly-fitting dowel into saidpassage to a depth such that the lower end of said dowel intimately andsealingly engages the upper end of said plug and the upper end of saiddowel is sunk below the exposed surface of said covering, and fillingthe portion of said passage above the upper end of said dowel withmortar conforming to said mortar bed.

14. The method of dispersing a liquid into the earth supporting a slabfloor, which comprises the steps of forming through such a slab and anycovering thereon a passage having a major transverse dimension notsubstantially exceeding one-fourth inch, seating within said passage atransversely-elastic plug conformable to said passage in cross section,having equilibrium transverse dimensions at least equal to thetransverse dimensions of said passage and having an axial length atleast equal to its transverse dimensions, forcing a tubular elementaxially through said plug to dispose the lower end of said elementwithin the portion of said passage below said plug with the elasticmaterial of said plug gripping the walls of said element, intermediatethe ends of said element, in substantially fluid-tight relation,confining a measured quantity of volatile liquid in a chamber with whichthe upper end of said element is in communication, forcing a gas intosaid chamber to displace such liquid through said element, continuingthe supply of gas to said chamber until gas only escapes through saidelement into said passage, withdrawing said tubular element from saidplug while leaving said plug seated in said passage, and promptlythereafter driving a snugly-fitting dowel into the upper end of saidpassage and into intimate, sealing engagement with the upper end of saidplug.

References Cited in the file of this patent UNITED STATES PATENTS2,059,095 Fellman Oct. 27, 1936 2,116,591 Barber May 10, 1938 2,755,968Fiant July 24, 1956 OTHER REFERENCES Termites and Termite Control,Kofaid et al., authors, 2nd edition, revised, University of CaliforniaPress, page 468.

1. THE METHOD OF DISPERSING A FLUID INTO THE EARTH SUPPORTING A SLABFLOOR, WHICH COMPRISES THE STEPS OF FORMING THROUGH SUCH A SLAB AND ANYCOVERING THEREON A PASSAGE HAVING A MAJOR TRANSVERSE DIMENSION NOTSUBSTANTIALLY EXCEEDING ONE-FOURTH INCH, SEATING WITHIN SAID PASSAGE ATRANSVERSELY-ELASTIC PLUG CONFORMABLE TO SAID PASSAGE IN CROSS SECTION,HAVING EQUILIBRIUM TRANSVERSE DIMENSIONS AT LEAST EQUAL TO THETRANSVERSE DIMENSIONS OF SAID PASSAGE AND HAVING AN AXIAL LENGTH ATLEAST EQUAL TO ITS TRANSVERSE DIMENSIONS, FORCING A TUBULAR ELEMENTAXIALLY THROUGH SAID PLUG AND INTO THE PORTION OF SAID PASSAGE BELOWSAID PLUG WITH THE ELASTIC MATERIAL OF SAID PLUG GRIPPING THE WALLS OFSAID TUBULAR ELEMENT IN SUBSTANTIALLY FLUID-TIGHT RELATION, FORCING AFUMIGANT THROUGH SAID TUBULAR ELEMENT TO PERMEATE THE EARTH BENEATH SAIDSLAB, WITHDRAWING SAID TUBULAR ELEMENT FROM SAID PLUG WHILE LEAVING SAIDPLUG IN PLACE IN SAID PASSAGE, AND PROMPTLY THEREAFTER DRIVING ASNUGLY-FITTING DOWEL INTO THE UPPER END OF SAID PASSAGE AND INTOINTIMATE, SEALING ENGAGEMENT WITH THE UPPER END OF SAID PLUG.